As commonly known by a person skilled in the art, vertical axis washing machines, which are also known as “top load” washing machines, comprise electromechanical rotating machines able to develop at least one washing cycle comprised of filling steps, washing steps, draining steps and centrifugation steps.
According to the extensive literature available, thus belonging to the current state of the art, it can be noted that conventional embodiments of vertical axis washing machines comprise at least one washing basket for the reception of the wash load (clothes and other textile articles) and washing fluids.
Furthermore, conventional washing baskets also provide, in its interior, the existence of a kind of hollow column whose outer face is provided with ribs, blades, or walls that help to wash, by friction, the wash loads. Said hollow column is technically known as agitator.
Since the agitator is hollow, it is common to use its interior for the purpose of circulating the washing fluid.
In this regard, it is also common to use filter elements within the agitator. This allows that the washing fluid, throughout its movement inside the agitator, can be simultaneously filtered with the execution of the washing steps.
In general, during the washing steps, the washing fluid circulation is continuous, as follows: the washing fluid contained in the washing basket is inserted into the agitator (through the top of the agitator), passing through the filter element. Then, the washing fluid is reinserted into the washing basket (through the bottom of the agitator). In this flow circulation of the washing fluid, during the washing steps, the interior of the agitator is used as a kind of filter chamber.
In the draining steps, as seen in the embodiments of currently existing vertical axis washing machines, the agitator and its filter element are not used.
This is because, in conventional embodiments of vertical axis washing machines, drainage of washing fluid occurs through holes arranged in the bottom of the washing basket.
One example of a conventional drainage system can be found in the patent document U.S. Pat. No. 3,952,557, which discloses a vertical axis washing machine integrated with a drainage system in which the washing fluid is drained through holes present in the bottom of the basket. In this particular case, it is further noted that the agitator has no hole for the passage of water therein.
Although the embodiment described in the patent document U.S. Pat. No. 3,952,557 does not provide any type of drain pump, it is noteworthy that the latest embodiments provide the use of hydraulic pumps connected to the holes provided in the bottom of the washing basket. In this case, the hydraulic pumps act as drain pumps, and accelerate the drainage of the washing fluids. Furthermore, as known by a person skilled in the art, the introduction of drain pumps in drainage systems allow the bottom of the wash tank not be substantially flat (as disclosed in the exemplification of the patent document U.S. Pat. No. 3,952,557).
The current state of the art also includes alternative construction of drainage systems. In this context, it is worth mentioning the patent document U.S. Pat. No. 8,156,769, which discloses a vertical axis washing machine which has washing basket, and lower drain holes, drainage channels disposed in the side walls of the washing basket.
Anyway, drainage systems of washing fluids in vertical axis washing machines, using the internal volume of the agitator and, mainly, using the filter element usually existing inside the agitator are not known.
The present utility model patent arises based on this context.